I’m writting this article after a very long time. This happens due to the work pressure in my daily life. There is not enough free time to write any article, even customize my own sites / portfolios.

Okay, today I will be showing you guys how to call native C (you can call C++ methods too) functions using Golang. To accomplish this, I would think that you guys have this things installed on your system:

  • go
  • gcc
  • pkg-config

Let’s create a project in your $GOPATH/src. I have created my project in $GOPATH/src/github.com/mazhar266/goc. There I’ve added a file named square.c with the following function:

int square(int a)
  return a * a;

Now we will call this function from our go program. Let’s create a blank main.go file. Let’s just start writting the basic structure like:

package main

import "fmt"

func main() {

Now include the C package and include our square.c file which contains our square function. Add this line after package declaration:

import "C"

This first line imports our C program (the square.c file, you will understand if you are a C programmer). The second line imports the basic functionality in Go to talk with C.

Now make a method / function which will call the C function and return the result. This is for making the main method clean.

func makeSquare(a int) int {
  //Convert Go ints to C ints
  aC := C.int(a)

  sum, err := C.square(aC)
  if err != nil {
    return 0

  //Convert C.int result to Go int
  res := int(sum)

  return res

You can easily understand what this method does. It converts integer argument a for Go to integer argument for C. And also converts the returned result from C integer to Go integer.

So, we can call the function from the main function like:

func main() {

Now if we run go run main.go we will see the output 81 in the console.

That’s the basic of calling a C function from Golang. For dealing with complex C programs which uses thirdparty libraries, your have to maintain CFLAGS and LDFLAGS from your go application. We will see that in another article.

You can find the sample source code here https://github.com/mazhar266/goc